This invention relates to certain piperidine and pyrrolidine derivatives. The compounds of the invention are muscarinic receptor antagonists which are selective for smooth muscle muscarinic sites over cardiac muscarinic sites and which do not haze any significant antihistaminic activity. Thus the compounds are useful in the treatment of diseases associated with altered motility and/or tone of smooth muscle which can, for example, be found in the gut, trachea and bladder. Such diseases include irritable bowel syndrome, diverticular disease, urinary incontinence, oesophageal achalasia and chronic obstructive airways disease.
South African patent application no. 86/4522 (A. H. Robins Co., Inc.) discloses certain piperidine and pyrrolidine derivatives but these are stated to be useful in treating cardiovascular dysfunctions, countering the effects of histamine in allergies and countering gastric secretion excesses. None of the compounds of the formula (I) set out below are specifically disclosed in the said ZA 86/4522.